Industrial frying

PTLC was used to enrich the polar fraction of deep-fried potato chips and vegetable oils used in industrial frying operahons. After PTLC, capillary GC, GC-MS, and NMR were used to quantify sterols and sterol oxides in fried-potato products, as well as the composition of sterols in the oil used for frying [72]. 

Kochhar, S. P. (1998). Security in industrial frying processes. Grasas Aceites. 49, 282-302. 

Rossell, J. B. (1998). Industrial frying process. Grasas y Aceites. 49,282-295. 

Advancement in the packaging materials and packing methods has enabled the industrial frying operations to extend the shelf life of the fried products so they can be stored, distributed, and marketed over several weeks to several months, without losing freshness in the product. This has provided a tremendous boost to the growth of the packaged fried food industry. 

As previously mentioned, frying oil is used in homes, restaurants (food services), and industrial frying operations. Home fried food is consumed almost immediately after preparation. At restaurants, the fried food is generally made to order and consumed within minutes of its preparation. Frying oil is always considered acceptable at homes or restaurants when it produces good flavor and texture in the food. There is little or no concern regarding the shelf life of the fried product at either of these locations. 

The following criteria (2) are applied for the selection of oil for industrial frying ... 

Linolenic acid content must be low in order to provide maximum oxidative stability to the oil. This is why soybean and canola oil, which contain about 8% linolenic acid in the natural state, are hydrogenated to reduce their linolenic acid content to less than 2% determined by the capillary GC Method (2). Poor frying stability in sunflower oil comes primarily from the high level of hnoleic acid. Therefore, sunflower oil must also be hydrogenated to reduce its linoleic acid content to 35% or lower for industrial frying. Table 1 lists the analyses of the most commonly used industrial frying oils. 

TABLE 1. Analyses of Common Industrial Frying Oils and Fats. 

It has been mentioned earlier that linoleic acid is more stable than linolenic acid, but far less stable than oleic acid. This is why regular sunflower oil, which contains as much as 65% linoleic acid, is not suitable for frying shelf-stable industrial products. However, Table 1 indicates that liquid cottonseed and corn oil are used for industrial frying, although both oils contain over 50% linoleic acid. 

Frying oil needs certain amounts of solid fat to fry foods that require crunchy texture or crispness. Table 1 lists the typical industrial frying fats and their analyses. 

Liquid soybean oil and liquid canola oil contain 8% linolenic acid. This makes both oils very prone to oxidation, especially in the frying application. Light hydrogenation can reduce the linolenic acid to less than 2% (measured by the capillary GC method). This makes the oils suitable for industrial frying of shelf-stable products. 

Three basic alternatives are available to make trans-bee oils for industrial frying as well as other uses. These are described below. 

These oilseeds have been developed over the past two decades. These oils are very low in linolenic acid (except high oleic canola). All of these oils can be used for industrial frying without hydrogenation. Fatty acid compositions of these oils are listed in Table 6. These oils are in hmited supply and they are expensive. Com oil, cottonseed oil, and palmolein have been included along with the others for comparison. 

The Better Bean Initiative from the United Soybean Board of USA is developing the mid-oleic soybean oil, which will not require hydrogenation for industrial frying apphcations. Full commercialization of this oil will take at least six to ten years. In the meantime, the food industry in the United States will have to be very creative to reduce trans-faXs in fried foods as well as in other products. 

The USFDA has not imposed any regulation on frying oil quality at restaurants or in the industrial frying operations. The USDA requires the fryer oil to be discarded when the free fatty acid (FFA) in the oil exceeds 2%. 

Industrial frying is one of the major segments in the frying industry. Fried food in the United States and other countries are prepared and marketed in various forms. The most popular of these products is the salty snack food segment. This segment consists of a wide variety of products such as potato chips, tortilla chips, com chips, extmded products, pretzels, fried or roasted nuts, and so on. Out of all these products, potato chips has been known to the people for a long time. 

An industrial frying system consists of a number of components. These include ... 

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